I am upgrading from an ENO doublenest with a poncholiner underquilt to a Sparrow. I would like to find a tarp that will cover the 11 foot Sparrow and be significantly lighter than my Kelty 12x12 Noah's. Secondly, I would like to find a full length, 20 to 30 degree underquilt to fit the same. These will be used primarily for backpacking, so weight and packability are major considerations. Thanks, Jeff